The Bay Area Hepatitis C Cooperafive Research Center (Bay Area HCV Center) will use cutfing-edge immunologic technologies in the context of well-designed and diverse retrospective case-control and prospecfive clinical cohorts to study the human immune response to HCV. We wish to ask the question: why is it that some respond well to standard-of-care therapy and some do not? To address this question, the Center will assemble a strong mulfidisciplinary team comprised of immunologists and clinical investigators at three different sites associated with the University of California at San Francisco (San Francisco General Hospital, UC Medical Center, and the San Francisco Veterans Affairs Medical Center), the California Pacific Medical Center, the Blood Systems Research Institute, and Kaiser Permanente of Northern California. Such diversity in focus and in locafion requires a strong administrafive and organizafional structure to successfully promote synergy between the programmafic elements. The Administrative Core will facilitate the overall organizational structure and administrafive activities of the Center, interface with NIH NIAID staff, foster cooperafion between projects and cores, encourage crificism and advice from its scientists, promote fiscal responsibility, and provide a flexible administrative structure to assure the confinued excellence of the Center and its ability to address the Specific Aims. Specifically, the Administrative Core will: (1) provide an organizafional and programmatic structure to promote scientific interactions; (2) provide oversight and planning, set priorities, and establish decisionmaking processes; and (3) ensure that the Center meets all criteria of the multi-project Cooperative Agreement (U19) grant mechanism.